Dishwasher with soil separation chamber



Feb. 1, 1955 J. A. PIETSCH SHER- WITH son, SEPARATION CHAMBER DISHWAFiled June 17, 1954 FIG.2

5 WT E mm A H P E S O J HIS ATTORNEY United States Patent WITH SOILSEPARATION CHAMBER Joseph A. Pietsch, Schenectady, N. Y., assignor toGeneral Electric Company, a corporation of New York Application June 17,1954, Serial No. 437,338

Claims. (Cl. 134186) DISHWASHER the bottom thereof which hurls washingliquid upwardly and outwardly in the vat to effect the washing of dishessupported in the tub.

In dishwashers of this character a predetermined quantity of washingliquid is continuously circulated during each wash or rinse cycle.Generally, some food soil as well as liquid is circulated throughout thetub during each cycle and is redeposited on the dishes. As a result, acertain percentage of such soil remains on the dishes at the end of thewashing operation.

The object of the present invention is to provide a dishwasher having animproved soil separation sump which effectively separates food soilsfrom the washing water so asnto prevent recirculation of such materialby the impe er.

Further objects and advantages of my invention will become apparent asthe following description proceeds, and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

Briefly stated, in accordance with one aspect of my invention, I providea dishwasher tub having a rotary impeller carried on its bottom wall andsurrounded by an annular sump chamber which decreases in depth in thedirection of rotation of liquid circulated by the impeller. Located inthe lowermost portion of the chamber and overlooked by the highestportion is a drain port through which food soils and washing liquid passout of the tub. During washing operations soil laden water is circulatedupwardly along the inclined annular trough, and as it passes over theedge at the uppermost portion the soil settles into the lowermostportion adjacent the drain port.

For a better understanding of my invention reference may be made to theaccompanying drawing in which:

Fig. 1 is an elevation, partly in section, of a dishwasher tub embodyingmy invention.

Fig. 2 is a diagrammatic developed section of the bottom wall of theannular chamber of my invention.

Referring to the drawing the numeral 1 designates a dishwasher tubprovided with a suitable cover 2 and formed by generally vertical sidewalls 3 and a depressed bottom wall 4. The tub may be rectangular incrosssection, for example, in which case the side walls 3 will be fourin number and generally rectangular in shape. Centrally located withintub I and carried by bottom wall 4 is a rotary impeller 5 rotated on agenerally vertical axis by a suitable electric motor 6. Depending frombottom wall 4 and in generally concentric relation to the axis ofrotation of impeller 5 is an annular chamber or sump 7 defined by anouter generally cylindrical wall 8, an inwardly spaced generallycylindrical wall 9, a bottom wall portion connecting walls 8 and 9, anda generally vertical wall portion 11. Bottom wall portion 10 is upwardlyinclined in the form of a spiral from its lowermost portion 12 to itsuppermost portion 13 which overlooks the lowermost portion and isconnected thereto by vertical wall portion 11. A drain port 14 islocated adjacent the lowermost portion 12 of inclined bottom wall 10 andmay be connected by a drain pipe 15 to a suitable drain pump 16.

Tub 1 is of course provided with suitable means such as racks forsupporting dishes and other objects to be washed therein, and suitablemeans for introducing water and detergent or other suitable washingliquids. Inasmuch as these elements and features are well known in theart and form no part of the present invention they have not been shownin the drawing. Also, it will be understood that if automatic operationof the apparatus is desired suitable automatic control means forinitiating and terminating the washing, rinsing and drying cycles may beprovided.

In operation, washing liquid is circulated in tub I by impeller 5, andas the washing of the dishes proceeds particles of food waste areentrained in the liquid. In the absence of an arrangement such as thatprovided by my invention such food soils would be constantlyrecirculated and redeposited on the dishes, leaving some soil on thedishes at the end of the washing cycle. However, in accordance with myinvention soil entrained in the washing liquid is collected in theannular sump 7 at the bottom of the tub and is retained adjacent thedrain port 14 until the washing liquid is drained from the tub at theend of the washing cycle. As impeller 5 circulates liquid in the tub agenerally circular flow pattern is established on the depressed bottomwall 4 where returning liquid is collected. Inasmuch as bottom wallportion 10 is upwardly and spirally inclined in the direction ofrotation of this liquid, the liquid swirls upwardly along the inclineand the soil particles, being heavier, tend to gravitate toward bottomwall portion 10. As the liquid and entrained solids pass over theuppermost portion 13 of sump 7 the soil particles rapidly fall out andaccumulate in the lowermost portion of the sump as illustrated in Fig.2. While the swirling liquid in annular chamber 7 flows at a relativelyhigh velocity, the lowermost section 12 in which the drain port islocated is a region of low turbulence and low water velocity below theflow path of the higher velocity currents, and the soil collectedtherein is not carried out again into the main stream. Thus during bothwashing and rinsing operations any food soil particles in the liquidbeing circulated are rapidly collected or deposited in the lowermostportion of sump 7 and are discharged from the tub when pump 16 isenergized.

While I have shown and described a particular embodiment of myinvention, it will be evident to those skilled in the art that variouschanges and modifications may be made without departing from myinvention in its broader aspects and I therefore aim in the appendedclaims to cover all such changes and modifications as fall within thetrue spirit and scope of my invention.

What I claim as my invention is:

l. A dishwasher comprising a tub having side walls and a depressedbottom wall, a rotary impeller carried by said bottom wall and operableto circulate liquid in said tub in a generally rotary path, an annularsump depending from said bottom wall and surrounding said impeller, anda drain port in the lowermost portion of said sump, the bottom wall ofsaid sump being in spiral form and upwardly inclined in the direction ofrotation of said liquid from a low point adjacent said port to a highpoint overlooking said port.

2. A dishwasher comprising a tub having side walls and a depressedbottom wall, a rotary impeller carried by said bottom wall and operableto circulate liquid in said vat in a generally rotary path, an annularsump depending from said bottom wall and including a pair of generallycylindrical concentrically spaced walls and an annular connecting bottomwall therebetween surrounding said impeller, and a drain port in thelowermost portion of said annular bottom wall, said annular bottom wallbeing in spiral form and upwardly inclined in the direction of rotationof said liquid from a low point adjacent said port to a high pointoverlooking said port.

3. A dishwasher comprising a tub having side walls and a depressedbottom wall, a rotary impeller carried by said bottom wall and operableto circulate liquid in said tub in a generally rotary path, said bottomwall having a still deeper depressed portion at the center thereof, saidportion including a pair of concentrically spaced upwardly directedwalls surrounding the axis of said impeller and a connecting bottom wallcooperating to define an annular sump surrounding the axis of saidimpeller, the lowermost portion of said sump being located below saidimpeller and exteriorly of the sweep thereof, and a drain port in saidlowermost portion of said sump, said bottom wall of said sump being inspiral form and upwardly inclined in the direction of rotation of saidliquid from a low point adjacent said port to a high point overlookingsaid port.

dishwasher comprising a tub having side walls and a depressed bottomwall, a rotary impeller carried by said bottom wall and operable tocirculate liquid in said tub in a generally rotary path, an annularinclined trough formed in said bottom wall and surrounding the axis ofrotation of said impeller, said trough being upwardly inclined in thedirection of rotation of the liquid impelled by said impeller, asubstantially vertical wall portion connecting the lowermost portion ofsaid trough and the uppermost portion thereof, and a drain opening insaid lowermost portion.

5. A dishwasher comprising a tub having four upright side walls defininga washing chamber substantially rectangular in horizontal cross-section,and also having a depressed bottom wall, an impeller rotating in thedepressed bottom wall on an axis substantially coinciding with thecentral vertical axis of said chamber, said impeller having blades whichengage cleansing liquid in said bottom wall so as to hurl it upwardlyand outwardly toward said side walls and with a generally rotary motionabout said axis, said bottom wall having a still deeper depressedsection at the center thereof, said section including an upwardlydirected first wall element and an upwardly directed second wall elementand a connecting curved third wall element cooperating to define anannular sump surrounding said impeller, the lowermost portion of saidsump being located below said impeller and exteriorly of the sweepthereof, said connecting wall element having a drain port formed thereinadjacent said lowermost portion of said sump, said connecting wallelement being upwardly inclined in spiral form in the direction ofrotation of said liquid from a low point adjacent said port to a highpoint overlooking said port, and a generally vertical wall elementconnecting the uppermost portion of said connecting wall element and thelowermost portion of said connecting wall element.

No references cited.

